Water Vapor Permeability and Moisture Sorption of Soy Protein Isolate/Poly (Vinyl Alcohol) Packaging Films
Packaging films based on agricultural materials have received much attention as potential packagingmaterials, principally because such biodegradable films are considered to be a promising solution to environmentalimpacts of synthetic polymer packaging. The aim of the present work was to investigate the moisturesensitivity of films of soy protein isolate (SPI) blended with poly (vinyl alcohol) (PVA) and plasticizedwith glycerol. Moisture adsorption and sorption isotherm data of SPI/PVA/glycerol were mathematically fittedto the GAB model. With increasing PVA content, the equilibrium moisture content (EMC) of film samplesclearly decreased. That trend indicates that the addition of PVA decreased the ability of SPI proteinmolecules to absorb and accept water. EMC data and contact angle measurements showed that the addition ofplasticizer not only loosened the microstructure of blended films, but also increased the hydrophilicity by exposingtheir hydroxyl groups. Water vapor permeability (WVP) and moisture sorption were measured basedon the PVA and glycerol content of the films. WVP values of SPI/PVA films with and without glycerol werein the range 8.25 and 10.9 g mm (m2 h kPa)-1, and were significantly affected by both PVA and glycerol.WVP values decreased with increasing PVA content. XRD analysis confirmed that the glycerol can enter themacromolecular blend structure and destroy the crystallinity of the blends. Cross-linking between glycerolmolecules and SPI reduced the interstitial spaces in the protein matrix, thus decreasing the rate of diffusion ofwater molecules through the films.
Jun-Feng Su Sheng-Bao Wang Xu-Zhen Lu Li-Dan Zhang Yun-Yi Zhang
Institute of Materials Science & Chemical Engineering, Department of Packaging Engineering,Tianjin U School of Materials Science & Engineering, Tianjin University, Tianjin 300072, China
国际会议
The 17th IAPRI World Conference on Packaging(第17届世界包装大会)
天津
英文
444-448
2010-10-12（万方平台首次上网日期，不代表论文的发表时间）